Paramagnetic textile roll coverings



F eb. 9, 1965 R. s. OLCOTT 3,168,760 PARAMAGNETIC TEXTILE RQLL COVERINGS Filed April 10, 1961 INVENTOR. ROBERT S. OLCOT'T United States Patent ()fiice 3,168,760 Patented Feb. 9, 1965 3,168,760 PARAMA'GNETIC TEXTILE ROLL COVERINGS Robert S. Olcott, Manor Township, Lancaster County, Pa., assignor to Armstrong Cork Company, Lancaster, Pa., a corporation of Pennsylvania Filed Apr. 10, 1961, Ser. No. 101,801 8 Claims. (Cl. 19-272) This invention relates to spinning cots and roll coverings for drawing rolls and other fiber handling rolls used for the drafting of textile fibers. More particularly, the invention relates to cots or coverings for the top rolls of drafting machines, which with their cooperating bottom rolls perform the operation of drafting slivers or roving to reduce their diameter and lay the fibers parallel. Still more particularly, this invention relates to top roll coverings have magnetically permeable particles homogeneously incorporated in a non-magnetic binder.

In drawing frames the drawing rolls normally consist of a series of pairs of upper and lower rolls arranged one in advance of the other to operate successively on a roving, sliver or the like to feed it and to draw it out or attenuate it during the feeding operation. The bottom rolls customarily are long, fluted steel rolls and are positively driven by gearing located at one end of the machine. The upper or top rolls, however, are short and customarily driven only by their contact with the bottom rolls.

The most common method of providing the pressure necessary between the upper and lower drafting rolls for proper drafting engagement and grip on the fibers in the past has been to provide a Weighting mechanism for the top rolls. However, these weighting arrangements which usually consisted of saddles or weight hooks connected bystirrups or rods with springs, Weights or weighted levers, caused objectionable power loss as well as considerable wear, necessitating frequent replacement of worn parts. Roll removal, difiicult cleaning, and nonuniform roll pressures also resulted from this method of roll weighting. These disadvantages have long been apparent to those skilled in the art, and various attempts have been made to find a means of achieving the proper pressure between the two rolls without the accompanying disadvantages mentioned above.

One concept of using magnetic force to obtain the required drafting pressures is disclosed in US. Patent 2,686,940 to V. A. Burnham. By this method, one or both rolls of as many pairs in a drawing mechanism as maybe desired consists of or includes a magnet, the rolls being so associated that the magnetic force pulling them together applies pressure on the material being drafted to enable the rolls to perform their drafting function. The use of conventional roll coverings in an arrangement of this type necessitates the provision of extended, enlarged ends on the soft iron pole pieces in order that these pole pieces may be in close working proximity to the bottom steel roll. The pole piecesare held out of engagement with the bottom roll by the thickness of the roll covering. In such an arrangement the available working thickness'of the roll covering is reduced to-the equivalent of the distance between the ends of the pole pieces and the bottom roll. Use of the magnetically permeable roll covering of the present invention 'would preclude the use of end pole piece extensions, provide more'available work ing thickness in the roll covering and increase the'eificiency of available magnetic force.

- Inthe present invention, it is an object to provide a more positive means of obtaining the desired drafting pressures between top and bottom drafting rolls. This is achieved in a new,'more efficient and desirable'manner by providing a highly permeable path for magnetic lines of force in their travel between a magnet-containing top roll and a steel bottom roll of the type normally used. This is accomplished by providing a covering for the top roll, which retains all the usual good fiber handling qualities desired in a roll covering of this kind, eliminates the air gap between the rolls, and takes full advantage of the desirable qualities of magnetically developed roll pressures by inclusion in the roll covering of homogeneously dispersed, finely-divided particles of magnetic material. In accordance with this invention, magnetically permeable material such as iron powder, iron oxide, or a combination of the two, together with the usual curing agents, fillers, vulcanizing agents, antistatic agents, etc., are incorporated in the cot composition at the time of compounding. The preferred particle size of the iron powder is about 325 mesh US. Standard andof the iron oxide about 1.2 microns for best fiber handling qualities in the finished roll covering. The size of the particles may be varied within the range of 100325 mesh for the iron powder and from .3 to 4 microns for the iron oxide. The quantity of the metallic elements used may be varied to achieve the quality desired.

The present invention will be more fully understood from the following description taken in connection with the accompanying drawing which is a diagrammatic View, partially in section, of a pair of drafting rolls showing an elastomeric top roll cover manufactured according to this invention.

Referring to the drawing more in detail, spinning roller or mandril 1 bears the coverings 2 thereon. In this construction, upper roll 1 consists of a magnet 4, two end pole pieces 5 and a sleeve 3 preferably of non-magnetic material, such as certain stainless steels, brass or aluminum alloys, having the desired mechanical characteristics telescoped on the adjaecnt end portions of said pole pieces 5 and welded or otherwise secured to them. Also, the inner end faces of these two pole pieces 5 are in engagement with the opposite ends of the magnet 4. Roll covers 2 are mounted on end pole pieces 5 and rotate therewith in rolling engagement with fluted sections 8 of bottom roll 7. Bottom roll 7 is held in frictional driving contact with top roll 1 and the desired drafting pressure maintained entirely by the magnetic flux created by the mag net 4 in the top roll. This flux flows through the end pole pieces 5 and paramagnetic cover composition 2 and through roll 7 which is made of magnetic material. Because of the increased efiiciency acquired in using the roll cover of this invention to utilize the attraction of the top roll with the bottom roll, the retarding forces on the rotation of the rolls normally attendant with the use of weighting arms, etc., is eliminated and a more positive I and economical driving arrangement is obtained.

In the manufacture of cots or roll covers according to this invention, the magnetically permeable materials are thoroughly admixed with the rubber-like composition WhICh is to form the roll cover. The composition is then molded and vulcanized to the required form.

While it will be apparent that this invention may be employed with advantage in connection with other vulcanizable cot materials, it has been found that the best synthetic rubber-like materials comprise a butadieneacrylonitrile copolymer or a chlorosulfonated polyethyl- Hypalon, compounded with fillers vulcanizing agents, paramagnetic powder, a surface-active agent, and other ingredients. Such cots also have excellent fiber drafting properties and exhibit substantially no tendency tocollect fiber on the surface thereof. It will be understood that the particular amount of butadiene'acrylonitrile copolymeror other'elastomer.

may be .varied considerably in order to control the,.char acteristics of the finished cot, but it is preferred touse from about l0% to 25% by weight of the composition,

7 Thehardness of the cots and other fiber handling roll I covers as measured on the Shore type A durometer is preferably Within the range of 60 to 85 and may be controlled as well as the toughness and resiliency of the finished article by addition of known materials other than those mentioned.

While it will be apparent that this invention is not necessarily limited to any specific composition, it isadvantageous to use as molding elastomers a butadieneacrylonitrile copolymer or a chlorosulfonated polyethylene in order to produce a cot having the desired drafting characteristics. Other useful elastomers such as polychloroprene, polyurethanes, polyethylene, and butadienestyrene copolymers may also be used, as well as natural rubber. Ferrites such as magnesium, zinc, and barium compounds may be used. A particularly useful compound is barium ferrite, BaO-6Fe O It will be understood by those skilled in the art that the improved cot or roll covering of this invention having magnetic characteristics may be used in a variety of fiber working machine elements for use in the textile industry. For example, various types of roll covers such as spinning cots, roving cots, and comber detaching roll covers may be manufactured from these compositions.

. It will also be understood by those skilled in the art that the degree of vulcanizationor curing may be so controlled as to produce a specific physical property desired in thesynthetic elastomeric composition. Also, the amounts of the different ingredients may be varied or equivalents may be substituted therefor in order to produce an elastomeric product of any desired degree of hardness, elasticity and frictional characteristics. In each case the ingredients are preferably compounded with butadiene-acrylonitrile copolyrners or ohlorosulfonated polyethylene thoroughly mixed with finely-divided magnetic material, molded to the desired shape or form, and treated to impart the desired surface characteristics.

In order to point out further the nature of the present invention, the following specific examples are given of illustrative formulae for producing the paramagnetic roll covers of this invention, in which all parts are by weight unless otherwise stated.

' Example 1 Ingredients: Parts Chlorosulfonated polyethylene (Hypalon 40) 100.0

Hydrogenated rosin A 2.5 Light magnesium oxide 20.0 "Titanium dioxide Q. 15.0 Powdered iron oxide (Mapico EG-3) 150.0 Dioctyl phthalate 15.0

Polyethylene glycol (400) monolaurate (Nonisol/100) 10.0 Sponge iron powder (325 mesh US. Standard) 100.0 Dipentamethylene thiuram tetrasulfide (Tetrone A) 1.0

v In preparing the above composition, the. Hypalon 40 was banded on a mill and the remaining ingredients added singly in the order in which they appear, withthe excep- 60 tion of the iron oxide, dioctyl phthalate and Nonisol/ 100 which were added simultaneously. A cot was made in the usual manner.

A cot of this type I a Example 2 Ingredients: 7 Parts Butadiene-acrylonitrile'copolyrner (Paracril B') 100.0 Zinc oxide 2 5.0 Rubbermakers sulfur 10.0 Calcium stearate. 2.0 Titanium dioxide 15.0 Powdered iron oxide (Mapico EG-B) 100.0

shows medium permeability characteristics while having. a low volume resistivity and antistaticproperties suitable for some high voltage applications where high resistance to corona cracking is required.

Liquid polymer of coumarone and indene resin The preparation of this compound proceeded as in Example l, with the of coumarone and indene resin, glycerol triacetate and Nonisol/ 100 being added together. A roll covering was made from the composition.

This roll covering possessed fine antistatic and superior fiber handling qualities combined with medium magnetic permeability qualities. It is a softer material useful for optimum fiber control.

, Example 3 Ingredients: 'Parts Butadiene acrylonitrile copolymer (Paracril BLT) 100.0 Zinc oxide 5.0 Titanium dioxide 15.0 Hydrated silica (Hi-Sil 233) 25.0

Liquid polymer of coumarone and indene resin (Dipolymer oil) 20.0 Glycerol triacetate (Triacetin) 20.0

Cashew nut oil modified phenol formaldehyde resin (Durez 12687) 15.0 Sponge iron powder (325 mesh) 600.0 Polyethylene glycol'(400) monolaurate (Nonisol/ 100) 10.0 N-Cyclohexyl-Z-benzothiazyl-sulfonamide (Santocure) 1.0 M. Tuads ,7.0

' The same procedure was followed in preparing this composition as in the preceding examples, with the" hydrated silica, dipolymer oil and Triacetin being added together and the Santocure and M. Tuads added last.

This composition resulted in a harder roll covering with Glycerol triacetate (Triacetin) 20.0 ..Cashew nut oil modified phenol formaldehyde resin (Durez 12687) 15.0 Sponge iron powder (100 mesh US. Standard) 600.0 Polyethylene glycol (400) monolaurate (Nonisol/100) 10.0 Mercaptobenzothiazole (Captax) 2.0 M. Tuads 1.5

This composition was prepared in the same manneras the preceding example with the Captax and M. .Tuads added last. The roll covering possessed'a high Shore type acteristics and fair fiber I claim: y -1. In a fiber drafting mechanism the combination comprising a fiber handling top roll and an underlying metal bottom'roll'cooperating therewith, said top roll comprishandling qualities.

- inglongitudinally' spaced'magnetic pole pieces of opposite polarity having opposing end portions, a cylindrical sleeve I of nonmagnetic material telescoped onsaid opposing end.

powdered iron oxide, liquid polymer A hardness with maximum magnetic permeability'char- 0.? portions of said longitudinally spaced magnetic pole pieces, a magnet contained in said sleeve in engagement with said pole pieces, elastomeric roll covers mounted on said pole pieces adjacent opposite ends thereof, said roll covers having powdered ferromagnetic material homogeneously dispersed throughout their bodies to provide a path for magnetic flux between said underlying metal bottom roll and said pole pieces, said underlying metal bottom roll having fluted portions thereon positioned in rotatable contact with said roll covers, said elastomeric roll covers being fabricated from a composition comprising a synthetic elastorner and about 200 to 600 parts by weight of finely divided ferromagnetic powder per 100 parts by weight of said elastomer, the particles of said ferromagnetic powder having an average particle size in the range of from about .3 micron to 100 mesh U.S..

Standard.

2. The combination according to claim 1 wherein the elastomeric portion of the roll covers composition is chlorosulfonated polyethylene.

3. The combination according to claim 1 wherein the elastomeric portion of the roll covers composition is a butadiene-acrylonitrile copolymer.

4. The combination according to claim 1 wherein the elastomeric portion of the roll covers composition is natural rubber.

5. The combination according to claim 1 wherein said ferromagnetic material is powdered iron.

6. The combination according to claim 1 wherein the ferromagnetic material is powdered iron oxide.

7. The combination according to claim 1 wherein the ferromagnetic material is powdered iron and iron oxide.

8. The combination according to claim 1 wherein the elastomeric portion of the roll covers composition consists of equal amounts of a butadiene-acrylonitrile copolymer, and the ferromagnetic material is powdered iron and iron oxide.

References Qited in the file of this patent UNITED STATES PATENTS 1,784,659 Devaux Dec. 9, 1930 2,291,005 Strang July 28, 1942 2,467,214 Luaces Apr. 12, 1949 2,686,940 Burnaham Aug. 24, 1954 2,800,800 Dunn July 30, 1957 2,921,479 Thomas Jan. 19, 1960 2,928,801 Satford et a1. Mar. 15, 1960 2,951,266 Burnaham Sept. 6, 1960 2,954,359 Robb et a1 Sept. 27, 1960 3,079,646 Burnham Mar. 5, 1963 

1. IN A FILTER DRAFTING MECHANISM THE COMBINATION COMPRISING A FIBER HANDLING TOP ROLL AND AN UNDERLYING METAL BOTTOM ROLL COOPERATING THEREWITH, SAID TOP ROLL COMPRISING LONGITUDINALLY SPACED MAGNETIC POLE PIECES OF OPPOSITE POLARITY HAVING OPPOSING END PORTIONS, A CYLINDRICAL SLEEVE OF NONMAGNETIC MATERIAL TELESCOPED ON SAID OPPOSING END PORTIONS OF SAID LONGITUDINALLY SPACED MAGNETIC POLE PIECES, A MAGNET CONTAINED IN SAID SLEEVE IN ENGAGEMENT WITH SAID POLE PIECES, ELASTOMERIC ROLL COVERS MOUNTED ON SAID POLE PIECES ADJACENT OPPOSITE ENDS THEREOF, SAID ROLL COVERS HAVING POWDERED FERROMAGNETIC MATERIAL HOMOGENEOUSLY DISPOERSED THROUGHOUT THEIR BODIES TO PRODIVE A PATH FOR MAGNETIC FLUX BETWEEN SAID UNDERLYING METAL BOTTOM ROLL AND SAID POLE PIECES, SAID UNDERLYING METAL BOTTOM ROLL HAVING FLUTED PORTIONS THEREON POSITIONED IN ROTATABLE CONTACT WITH SAID ROLL COVERS, SAID ELASTOMERIC ROLL COVERS BEING FABRICATED FROM A COMPOSITION COMPRISING A SYNTHETIC ELASTOMER AND ABOUT 200 TO 600 PARTS BY WEIGHT OF FINELY DIVIDED FERROMAGNETIC POWDER PER 100 PARTS BY WEIGHT OF SAID ELASTOMER, THE PARTICLES OF SAID FERROMAGNETIC POWDER HAVING AN AVERAGE PARTICLE SIZE IN THE RANGE OF FROM ABOUT .3 MICRON TO 100 MESH U.S. STANDARD. 